1. Field of the Invention
The present invention relates to a radiation image pick-up apparatus and system and, more particularly, to a radiation image pick-up apparatus and system used for medical diagnosis and industrial nondestructive examination.
In this specification, radiation includes electromagnetic waves such as an X-ray, α-ray, β-ray and γ-ray.
2. Related Background Art
Conventional X-ray image pick-up systems installed in a hospital and the like include an analog type system for irradiating a patient with X-rays and exposing a film to X-rays having passed through the patient, and a digital type system for converting X-rays having passed through a patient into electrical signals and accumulating the electrical signals.
FIG. 16 is a block diagram showing the schematic arrangement of a conventional analog X-ray image pick-up system. In FIG. 16, an X-ray source 101 emits X-rays. An X-ray generation device 104 generates X-rays to be emitted by the X-ray source 101. A switch 105 is generally opened/closed by a radiation technician to control emission of X-rays. X-ray information of an object 102 to be examined such as a patient is recorded on a film 120. Phosphor screens 103 convert X-rays having passed through the object 102 into light such as visible light.
The film 120 is not sensitive to the X-ray wavelength range, so that the film system interposes the phosphor screen 103 between the film 120 and the object 102. The film 120 senses the intensity of visible light or the like converted by the phosphor screen 103, forming an image as X-ray information of the object 102.
The phosphor screens 103 are tightly adhered to the film 120 with an adhesive so as not to decrease the sharpness of an X-ray image on the film 120. Two phosphor screens 103 are arranged on the front and back sides of the film 120 so as to obtain a high-quality X-ray image.
FIG. 17 is a block diagram showing the schematic arrangement of a conventional digital X-ray image pick-up system. Instead of the film 120 in FIG. 16, the X-ray image pick-up system shown in FIG. 17 adopts a solid-state image pick-up device 130 having a CCD image pick-up element or MOS image pick-up element for converting X-rays having passed through the object 102, and a controller 140 for controlling driving of the solid-state image pick-up device 130 in accordance with a control signal transmitted along with opening/closing of a switch 105. In FIG. 17, the same reference numerals as in FIG. 16 denote the same parts.
If the switch 105 is unintentionally closed in the X-ray image pick-up system shown in FIG. 17, the X-ray generation device 104 transmits a control signal to the controller 140 in order to synchronize the driving timing of the solid-state image pick-up device 130 with the emission timing of X-rays.
If X-ray information of a patient is to be used for diagnosis by a doctor or the like in the analog X-ray image pick-up system, X-ray information of the patient on the film must be developed, which requires a developing time after image pick-up by a radiation technician to diagnosis by the doctor. This also requires cumbersome processing of a waste developing solution and a space for stocking films.
In the digital X-ray image pick-up system, the X-ray generation device 104 and controller 140 are wired in order to transmit a control signal from the X-ray generation device 104 to the controller 140 so as to establish synchronization. The wiring obstructs image pick-up particularly when the solid-state image pick-up device is to be used as a lightweight low-profile image pick-up device such as a film cassette. Such an image pick-up device is not easy to carry, and may decrease the image pick-up efficiency.
When the manufacturer of the X-ray generation device and that of the solid-state image pick-up device are different, an interface circuit must be prepared in some cases in order to enable transmission/reception of control signals. To replace, e.g., an X-ray source used with one of another manufacturer after an X-ray image pick-up system is installed in a hospital, an interface for allowing transmission/reception of control signals to/from a new X-ray source is undesirably required.
In the emergency medical field, a portable lightweight low-profile cassette is convenient when a space is limited as in an ambulance or when a doctor or the like is to acquire X-ray information of a patient even in a place remote from the hospital. At this time, demands are arising for an X-ray image pick-up system which does not use electrical wiring as much as possible.